[LyX/2.3.x] Fix configure script with autoconf 2.71

[Jean-Marc Lasgouttes]

commit 9fc89762ee731daa36092c598028e0b95afc69f2
Author: Jean-Marc Lasgouttes <lasgouttes at lyx.org>
Date:   Fri Jun 24 13:27:55 2022 +0200

    Fix configure script with autoconf 2.71
    
    Not a backport, but related to e4416535.
---
 config/lyxinclude.m4 |    2 +-
 config/qt4.m4        |    2 +-
 m4/eilseq.m4         |   20 ++++++++++----------
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/config/lyxinclude.m4 b/config/lyxinclude.m4
index b5d3ab0..d547662 100644
--- a/config/lyxinclude.m4
+++ b/config/lyxinclude.m4
@@ -49,7 +49,7 @@ AC_MSG_CHECKING([for version suffix])
 dnl We need the literal double quotes in the rpm spec file
 RPM_VERSION_SUFFIX='""'
 AC_ARG_WITH(version-suffix,
-  [AS_HELP_STRING([--with-version-suffix@<:@=STR@:>@],[install lyx files as lyxSTR (default STR: -AC_PACKAGE_VERSION)])],
+  [AS_HELP_STRING([--with-version-suffix@<:@=STR@:>@], install lyx files as lyxSTR (default STR: -AC_PACKAGE_VERSION))],
   [if test "x$withval" = "xyes";
    then
      withval="-"AC_PACKAGE_VERSION
diff --git a/config/qt4.m4 b/config/qt4.m4
index 47a3d16..0d77b8c 100644
--- a/config/qt4.m4
+++ b/config/qt4.m4
@@ -179,7 +179,7 @@ AC_DEFUN([QT_DO_IT_ALL],
 	CPPFLAGS="$save_CPPFLAGS $QT_CORE_INCLUDES"
 	AC_CHECK_HEADER(QtGui/qtgui-config.h,
 	  [lyx_qt5_config=QtGui/qtgui-config.h],
-	  [lyx_qt5_config=qconfig.h],[-])
+	  [lyx_qt5_config=qconfig.h])
 	AC_MSG_CHECKING([whether Qt uses the X Window system])
 	if test x$USE_QT5 = xyes ; then
 	  AC_EGREP_CPP(xcb,
diff --git a/m4/eilseq.m4 b/m4/eilseq.m4
index 792d514..5f86ab3 100644
--- a/m4/eilseq.m4
+++ b/m4/eilseq.m4
@@ -1,6 +1,6 @@
-#serial 1
+#serial 2
 
-AC_PREREQ(2.50)
+AC_PREREQ([2.61])
 
 # The EILSEQ errno value ought to be defined in <errno.h>, according to
 # ISO C 99 and POSIX.  But some systems (like SunOS 4) don't define it,
@@ -16,20 +16,20 @@ AC_DEFUN([AC_EILSEQ],
   AC_REQUIRE([AC_PROG_CC])dnl
 
   dnl Check for any extra headers that could define EILSEQ.
-  AC_CHECK_HEADERS(wchar.h)
+  AC_CHECK_HEADERS([wchar.h])
 
-  AC_CACHE_CHECK([for EILSEQ], ac_cv_decl_EILSEQ, [
-    AC_EGREP_CPP(yes,[
+  AC_CACHE_CHECK([for EILSEQ], [ac_cv_decl_EILSEQ], [
+    AC_EGREP_CPP([yes],[
 #include <errno.h>
 #ifdef EILSEQ
 yes
 #endif
-      ], have_eilseq=1)
+      ], [have_eilseq=1])
     if test -n "$have_eilseq"; then
       dnl EILSEQ exists in <errno.h>. Don't need to define EILSEQ ourselves.
       ac_cv_decl_EILSEQ=yes
     else
-      AC_EGREP_CPP(yes,[
+      AC_EGREP_CPP([yes],[
 #include <errno.h>
 #if HAVE_WCHAR_H
 #include <wchar.h>
@@ -37,11 +37,11 @@ yes
 #ifdef EILSEQ
 yes
 #endif
-        ], have_eilseq=1)
+        ], [have_eilseq=1])
       if test -n "$have_eilseq"; then
         dnl EILSEQ exists in some other system header.
         dnl Define it to the same value.
-        _AC_COMPUTE_INT([EILSEQ], ac_cv_decl_EILSEQ, [
+        AC_COMPUTE_INT([ac_cv_decl_EILSEQ], [EILSEQ], [
 #include <errno.h>
 #if HAVE_WCHAR_H
 #include <wchar.h>
@@ -62,6 +62,6 @@ yes
     AC_DEFINE_UNQUOTED([EILSEQ], [$ac_cv_decl_EILSEQ],
                        [Define as good substitute value for EILSEQ.])
     EILSEQ="$ac_cv_decl_EILSEQ"
-    AC_SUBST(EILSEQ)
+    AC_SUBST([EILSEQ])
   fi
 ])